Micrometer



FIG. 1 is a front view of a micrometer;

FIG. 2 is a rear view thereof;

FIG. 3 is a top view thereof; and,

FIG. 4 is a bottom view thereof.

The broken lines depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for a micrometer, as shown and described. 